Re: REQ: SSH behaviour dependent from the connecting client

Albert Lunde <atlunde@panix.com> wrote on 09/11/2004 06:54:13 PM:

> I think everything but the chroot functionality could be done with a
> custom restricted shell that execs other commands or shells as needed.
>
> Limiting a user to sftp and/or scp is basically a matter of writing a
> "shell" that accepts commands with -c but ignores all but a few
> commands, and runs them with hard-wired paths.

Hmm.  Smells like scponly.  My previous post assumed you'd look up what
scponly is if you've never heard of it before, since I mentioned it
specifically for use as the shell.  Please look at
http://www.sublimation.org/scponly/ and read up!  Then re-read my previous
post.

If you believe scponly fails some basic security checks, such as those you
mentioned, then please let us know!  I have not reviewed the scponly source
code so I cannot speak for it one way or the other.

> It does seem more straightforward to do some of this work in sshd, before
> the exec of the user's shell, while the code is still running as root.

Agreed, but that's not going to happen until someone somewhat integrates
scponly (or something like it) within SSHD, specifically within OpenSSH.
Supposedly that is already done for ssh.com's product, but I don't use that
one so I don't know how well it works.  Anyway, I'm surprised that no one
has done it yet.

--
Michael Buselli